John, however, was no Essene, as we know both from his garb and from his diet. He was in the line, rather, of Elijah… And the rite of baptism that he preached… was an ancient rite coming down from the old Sumerian temple city Eridu, of the water god Ea
Campbell situates the Baptist in the prophetic lineage of Elijah and traces the rite of baptism to Sumerian water-god mythology, ultimately suggesting through etymology that ‘John’ may be identical with the god Oannes.
, Occidental Mythology: The Masks of God, Volume III, 1964thesis